The aim of this research project is to determine the NMR solution structure of the binding domain of the intracellular protein CD2BP2 and to characterize the interaction of CD2BP2 with the cytoplasmic domain of the CD2 cell surface receptor. This interaction is critical for CD2 mediated interleukin-2 production upon T cell activation. During 1998, the 3D-structure of the isolated binding domain of CD2BP2 was solved and the binding site for the CD2 cytoplasmic domain was mapped by chemical shift analysis. The data of the homonuclear and the heteronuclear edited NOESY spectra recorded at the UP750 NMR spectrometer were critical for obtaining a high resolution structure of the binding domain of CD2BP2. The structure of this domain revealed a novel fold for the recognition of proline-rich sequences and probably represents a first member of a yet undefined family of protein domains. Future experiments will focus on the structure of the CD2BP2 binding domain in complex with its recognition sequence within the CD2 cytoplasmic domain. Data recorded at high magnetic fields will certainly be indispensable for the investigation of this interesting molecular interaction.